Computer simulation starts to play an indispensable role in modern materials science research due to the explosive growth of supercomputing capacity. It does not only supplement experimental investigations, but also provides great predicting power to guide experiments. In CAMP-Nano, a combined research effort with the employment of both computational modeling and experimental investigations on advanced materials is emphasized. In particular, atomic scale modeling methods, such as first-principles and classical molecular dynamics simulations are being undertaken to understand the structural, mechanical, thermodynamic and electronic properties of materials. 

First principles simulations:

First principles (or ab initio) simulations, such as Density Functional Theory (DFT) and DFT based ab initio molecular dynamics (AIMD), acquire a central role in modern materials science research. Such simulations are capable of characterizing real materials with the accuracy of quantum mechanics level without any experimental input. We are interested in materials modeling and materials design from first principles, with a special focus on large scale simulations -- realistic time- (nanoseconds) and length- scale (nanometers). Our research covers traditional materials, such as metallic alloys, and novel materials, such as phase change memory materials, topological insulators, graphene nanostructures, other 2D materials, dilute magnetic semiconductors and so on.

Classical molecular dynamics simulations:

With the employment of empirical or semi-empirical interatomic potentials, classical molecular dynamics simulation method can model materials system with up to billions of atoms. This allows a comparatively large scale (say, a few tens/hundreds nanometers or even micrometer) materials phenomena to be investigated directly. A major focus of our research is to investigate defects, defect interactions, and the mechanical behavior of various structural materials. For example, combined in-situ TEM mechanical test and molecular dynamics simulation have been used to unveil the underlying physics of the size effect of the mechanical behavior of BCC metals, the role of the boundary structure and kinetics played in the mechanical performance of nanostructured metals. Other research topics include: dislocation/precipitate interaction, twinning/precipitate interaction, and dislocation/helium bubble interaction in structural materials, etc.

 
 
 
References

1. L. Huang, Q. J. Li, Z. W. Shan, J. Li, J. Sun and E. Ma, A new regime for mechanical annealing and strong sample-size strengthening in body-centred cubic molybdenum, Nature Communications 2, 547 (2011).

2. C. C. Wang, Y. W. Mao, Z. W. Shan, M. Dao, J. Li, J. Sun, E. Ma and S. Suresh, Real-time, high-resolution study of nanocrystallization and fatigue cracking in a cyclically strained metallic glass, PNAS 110, 19725-19730 (2013).

3. L. Wan and J. Li, Shear responses of [¯1 1 0]-tilt {1 1 5}/{1 1 1} asymmetric tilt grain boundaries in fcc metals by atomistic simulations, Modelling and Simulation in Materials Science and Engineering 21, 055013 (2013).